Gingrich, Christie lead Trump's VP picks

Republican stalwarts Newt Gingrich and Chris Christie are at the top of Donald Trump's short list to be his vice presidential running mate, sources say, but the real estate developer is casting a wide net that also includes Indiana Governor Mike Pence.

With less than three weeks to go until he is formally nominated at the Republican National Convention as the party's candidate in the November 8 election, Trump's search for a No. 2 has intensified.

The wealthy businessman, a neophyte as a politician, has said he wants a seasoned political veteran to help him navigate the power corridors of Washington.

Gingrich and Christie, both loyal to Trump at a time when many Republican colleagues want nothing to do with him, would meet the New Yorker's requirement for experience - but would come with pluses and minuses.

Other names to watch include Pence, Senator Bob Corker of Tennessee, Senator Joni Ernst of Iowa and Oklahoma Governor Mary Fallin, Republicans close to the campaign said this week.

"Mr Trump is meeting with a number of Republican leaders in the run-up to the convention in Cleveland, and he has a good relationship with Gov. Pence," Trump spokesman Jason Miller said in an email.

Gingrich, who was speaker of the House of Representatives in the 1990s and ran for president in 2012, is a popular conservative writer and speaker, and has been an important behind-the-scenes voice in urging Trump to adopt a more presidential demeanor.